STS4DPF20L Equivalent & Substitute Parts

Part Overview

The STS4DPF20L is a dual P-channel MOSFET array manufactured by STMicroelectronics, rated for 20V drain-to-source voltage and 4A continuous drain current. This component is part of the STripFET™ series and is classified as obsolete. Due to its obsolete status, equivalent substitute parts are necessary for ongoing production, maintenance, and new design implementations where this device is specified or required as a replacement in existing applications.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	20	V
Current - Continuous Drain (Id) @ 25°C	4	A
Rds On (Max) @ Id, Vgs	80	mOhm @ 2A, 10V
Vgs(th) (Max) @ Id	2.5	V @ 250µA
Gate Charge (Qg) (Max) @ Vgs	16	nC @ 5V
Input Capacitance (Ciss) (Max) @ Vds	1350	pF @ 25V
Power - Max	1.6	W
Operating Temperature Range	-55 to 150	°C (TJ)
Configuration	2 P-Channel (Dual)	—
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
FET Feature	Logic Level Gate	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the STS4DPF20L are selected based on the following criteria:

Primary Compatibility Parameters:

Configuration: 2 P-Channel (Dual) MOSFET array
Package: 8-SOIC form factor (0.154", 3.90mm Width)
FET Feature: Logic Level Gate
Operating Temperature Range: -55°C to 150°C (TJ)
Technology: MOSFET (Metal Oxide)
Mounting Type: Surface Mount

Electrical Performance Parameters:

Drain to Source Voltage (Vdss): 20V or higher
Continuous Drain Current (Id): 4A or higher
Gate Threshold Voltage (Vgs(th)): Compatible with logic-level gate drive requirements
On-Resistance (Rds On): Comparable performance characteristics
Power Dissipation: Adequate thermal handling

Regulatory & Compliance Parameters:

RoHS3 Compliance
Moisture Sensitivity Level (MSL): 1 (Unlimited)
REACH Status: REACH Unaffected

Substitute parts must maintain electrical and mechanical compatibility within the specified parameter ranges to ensure direct replacement capability in existing circuit designs.

Parameter Comparison

Parameter	STS4DPF20L (Main)	AO4803A	DMG9933USD-13	FDS9933A
Manufacturer	STMicroelectronics	Alpha & Omega Semiconductor Inc.	Diodes Incorporated	onsemi
Configuration	2 P-Channel (Dual)	2 P-Channel (Dual)	2 P-Channel (Dual)	2 P-Channel (Dual)
Vdss (V)	20	30	20	20
Id @ 25°C (A)	4	5	4.6	3.8
Rds On (Max) (mOhm)	80 @ 2A, 10V	46 @ 5A, 10V	75 @ 4.8A, 4.5V	75 @ 3.8A, 4.5V
Vgs(th) (Max) (V)	2.5 @ 250µA	2.5 @ 250µA	1.1 @ 250µA	1.5 @ 250µA
Gate Charge (Qg) (nC)	16 @ 5V	11 @ 10V	6.5 @ 4.5V	10 @ 4.5V
Input Capacitance (Ciss) (pF)	1350 @ 25V	520 @ 15V	608.4 @ 6V	600 @ 10V
Power - Max (W)	1.6	2	1.15	0.9
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC
FET Feature	Logic Level Gate	Logic Level Gate	Logic Level Gate	Logic Level Gate
Product Status	Obsolete	Not For New Designs	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

DMG9933USD-13 (Diodes Incorporated)

The DMG9933USD-13 is the primary recommended substitute for the STS4DPF20L. This part maintains identical Vdss (20V) and exceeds the continuous drain current specification (4.6A vs. 4A). The device is classified as Active, ensuring long-term availability and supply chain stability. It is fully RoHS3 compliant with MSL 1 rating. The 8-SOIC package form factor is identical, enabling direct PCB compatibility. On-resistance performance (75mOhm @ 4.8A, 4.5V) is comparable to the main part, and gate charge characteristics support equivalent switching performance in logic-level gate drive applications.

FDS9933A (onsemi)

The FDS9933A is an alternative substitute offering Active product status. It maintains the 20V Vdss rating and provides 3.8A continuous drain current, which meets the minimum 4A specification with marginal headroom. The device features lower gate charge (10nC @ 4.5V) and reduced input capacitance (600pF @ 10V), resulting in faster switching characteristics. On-resistance is 75mOhm @ 3.8A, 4.5V. This part is suitable for applications where lower power dissipation and faster switching are beneficial. RoHS3 compliance and MSL 1 rating are maintained. The PowerTrench® series designation indicates advanced process technology.

AO4803A (Alpha & Omega Semiconductor Inc.)

The AO4803A provides higher voltage rating (30V Vdss) and superior current handling (5A continuous drain current). On-resistance is significantly lower (46mOhm @ 5A, 10V), offering reduced power dissipation. However, this part is classified as Not For New Designs, limiting its suitability for new applications. It remains suitable for legacy system maintenance and replacement scenarios where supply availability is confirmed. RoHS3 compliance and MSL 1 rating are maintained. The 8-SOIC package is compatible.

Selection Criteria Summary:

For new designs and ongoing production: DMG9933USD-13 is recommended due to Active status, matched electrical specifications, and confirmed long-term availability.

For applications requiring lower power dissipation and faster switching: FDS9933A is suitable, with the caveat that continuous drain current is marginally below the original specification.

For legacy system maintenance where higher voltage margin is required: AO4803A is acceptable, subject to supply chain verification.

Frequently Asked Questions (FAQ)

Q: Can the DMG9933USD-13 be used as a direct replacement for the STS4DPF20L?

A: Yes. The DMG9933USD-13 maintains identical Vdss (20V), exceeds the continuous drain current requirement (4.6A vs. 4A), and is packaged in the same 8-SOIC form factor. Both devices feature logic-level gate drive capability and identical operating temperature range. Pin-to-pin compatibility is maintained, enabling direct PCB substitution.

Q: What is the difference between the 8-SOIC and 8-SO package designations used in the substitute parts?

A: The 8-SOIC and 8-SO designations refer to the same physical package form factor (0.154", 3.90mm Width). Both are surface-mount packages with identical pin spacing and footprint. The terminology variation reflects different manufacturer naming conventions but does not indicate physical incompatibility.

Q: Why is the AO4803A listed as "Not For New Designs"?

A: The "Not For New Designs" status indicates that the manufacturer has designated this part for legacy applications only. While the device remains functional and available, manufacturers recommend using alternative parts for new circuit designs. This status does not affect the part's electrical performance but reflects the manufacturer's product lifecycle strategy.

Q: Is the FDS9933A suitable if my application requires exactly 4A continuous drain current?

A: The FDS9933A is rated for 3.8A continuous drain current, which is below the 4A specification of the STS4DPF20L. For applications with strict 4A requirements, the DMG9933USD-13 (4.6A) or AO4803A (5A) are more appropriate selections. The FDS9933A is suitable for applications where the actual current demand is confirmed to be below 3.8A.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (AO4803A, DMG9933USD-13, and FDS9933A) are RoHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating. All parts are REACH unaffected and classified under ECCN EAR99 or equivalent export control categories.

Q: What is the significance of gate charge (Qg) differences between the substitute parts?

A: Gate charge affects switching speed and gate drive circuit requirements. The STS4DPF20L has 16nC @ 5V gate charge. The DMG9933USD-13 has 6.5nC @ 4.5V, and FDS9933A has 10nC @ 4.5V. Lower gate charge enables faster switching transitions and reduces gate drive power consumption. If the existing gate drive circuit is optimized for the original part's gate charge, verify that the substitute part's gate charge is compatible with the driver's output characteristics.

Q: Can I use the AO4803A in a 20V circuit even though it is rated for 30V?

A: Yes. The AO4803A's 30V Vdss rating indicates the maximum voltage the device can withstand. Operating at 20V is well within the device's safe operating area. The higher voltage rating provides additional safety margin and does not negatively affect circuit performance. However, the "Not For New Designs" status should be considered for long-term supply chain planning.

Q: What are the key differences in on-resistance (Rds On) between the substitute parts?

A: On-resistance directly affects power dissipation and heat generation. The STS4DPF20L has 80mOhm @ 2A, 10V. The AO4803A has 46mOhm @ 5A, 10V (lowest), DMG9933USD-13 has 75mOhm @ 4.8A, 4.5V, and FDS9933A has 75mOhm @ 3.8A, 4.5V. Lower on-resistance reduces power loss. For applications with thermal constraints, the AO4803A offers superior performance, while the DMG9933USD-13 and FDS9933A provide comparable performance to the original part.

Q: Are there any packaging or tape & reel considerations for these substitute parts?

A: The DMG9933USD-13 is supplied in Tape & Reel (TR) format, FDS9933A in Cut Tape (CT) & Digi-Reel® format, and AO4803A in Tape & Reel (TR) format. These packaging options are standard for high-volume production and automated assembly. Verify that your procurement and assembly processes support the specific packaging format of the selected substitute part.

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